Groove areas of winding coil or rod insulations to be cured with the help of gas-, oil- or electrically heated single-stage or multistage presses are conventionally brought to a required temperature in order to cure the insulation material. The winding coil or rod is heated at a predefined pressure for a certain period of time. Depending on the coil section, heating times of up to one hour are common. Subsequently, the coils are cooled again under pressure by a press. In this process the entire coil is heated. This is desirable, for example, in the case of winding coils or rods for main poles of DC motors. In winding coils or rods for three-phase motors, where only those parts of winding coils or rods that are in the grooves are to be heated, a heat flow is created in the coil face area due to the long heating process.
Commercially available conductor insulating materials have the disadvantage, due to the conductor heat flow even outside the groove-side area, that they conglutinate in the draw radius area. This results in damage to the conductor insulation that may range from quality-impairing to unacceptable when the coil is drawn. Attempts to stop the heat flow or to prevent it by cooling outside the groove-side area have shown that these measures are very costly and yield no reproducible quality results. When changing coil sections, for example, the process data (heating period, heating intensity) must always be determined anew.